The United States underwent profound transformations politically, economically, and socially following Reconstruction. The Gilded Age (late 19th century) was marked by rapid industrialization, urbanization, and the rise of monopolies, accompanied by stark economic inequality and labor unrest. The Progressive Era and the New Deal sought to address these issues through reforms and expanded government intervention. The early 20th century saw the U.S. asserting itself on the global stage with involvement in World War I and World War II, leading to its emergence as a superpower. The Cold War era (1947-1991) was defined by geopolitical tension with the Soviet Union, the Korean and Vietnam Wars, and significant domestic changes, including the Civil Rights Movement, feminist movement, and shifts in cultural and political norms. The post-Cold War period saw economic expansion but also rising political polarization. The terrorist attacks on September 11, 2001, marked a pivotal moment, leading to the War on Terror and significant changes in domestic and foreign policies. Throughout these periods, the U.S. navigated challenges and changes that shaped its modern identity and role in the world.Â